Method for preventing fibers consisting of or comprising copolyamide from stickiness

ABSTRACT

A method for producing nonsticky copolyamide-containing fibers wherein at least one normal paraffin selected from the group consisting of methane series hydrocarbons represented by the formula CnH2n 2, wherein n is an integer of at least 14, is dispersed homogeneously in a copolyamide melt. The so-melted copolyamide is then extruded through a spinning nozzle simultaneously with a homopolyamide melt.

United States Patent Inventors App]. No. Filed Patented Assignees METHOD FOR PREVENTING FIBERS CONSISTING OF OR COMPRISING COPOLYAMIDE FROM STICKINESS 3 Claims, 2 Drawing Figs.

U.S.Cl 161/173, 264/168, 264/17 1, 264/211 Int. Cl B291 3/10, D02g 3/00 Field of Search 264/21 1,

209, 171, 168, 167, 170; 260/18N; l6l/167178 [56] References Cited UNITED STATES PATENTS 3,418,199 12/1968 Anfon etal. 161/175 3,423,923 1/1969 Hume i i 57/140 2,205,722 6/1940 Graves 264/169 X 2,856,373 10/1958 Lowery et al, 260/18 N 3,052,646 9/1962 Doggett i 260/18 N X 3,140,957 7/1964 Tanabe etal. 117/6 3,225,534 12/1965 Knospe 57/140 3,423,491 1/1969 McLain et al 264/209 X FOREIGN PATENTS 834,350 5/1960 Great Britain 264/211 963,320 7/1964 Great Britain 264/21 1 Primary Examiner-Jay H. Woo AttorneyStevens, Davis, Miller & Mosher ABSTRACT: A method for producing nonsticky copolyamide-containing fibers wherein at least one normal paraffin selected from the group consisting of methane series hydrocarbons represented by the formula C l-1 wherein n is an integer of at least 14, is dispersed homogeneously in a copolyamide melt. The so-melted copolyamide is then extruded through a spinning nozzle simultaneously with a homopolyamide melt.

E o I l I I I I", I T 'i- 5 IO 15 51 Time (minute) METHOD FOR PREVENTING FIBERS CONSISTING OF OR COMPRISING COPOLYAMIDE FROM STICKINESS This application is a division of our copending application, Ser. No. 601,756, filed Dec. 14, 1966 and now abandoned.

The present invention relates to a method for preventing fibers produced from copolyamides from stickiness.

The polyamide fibers have been heretofore used in a wide field owing to its excellent properties, but most of these fibers have been formed from homopolyamides.

On the other hand, however, the homopolyamides have a number of disadvantages if dyeability, hygroscopicity, elastic recovering property and etc., so that a large number of copolyamides copolymerized with at least two polyamide forming materials have been proposed in order to improve these disadvantages. It is considered that, in general, the fibers consistin'gof these copolyamides have excellent properties in dyeability, hygroscopicity, elastic recovering property, etc. as compared with homopolyamide fibers and also the shrinking property in hot water is increased, so that they suit for particu lar uses. A serious disadvantage to retard practice of the copolyamide fibers consists in an inherent stickiness of the copolyamides, so that in spite of that said fibers have a large number of advantages, these fibers have heretofore not been produced commercially.

Namely, when the copolyamides are melt spun and then treated with an oil composition, such as, an aqueous emulsion and thereafter taken up on a bobbin, the fibers stick with each other, so that when said fibers are subjected to next processes, such as, drawing and the other processes, an unevenness occurs in yarn tension when unwinding yarn from a bobbin and a uniform treatment can not be effected and moreover in the worst case, the yarn is broken and the operatability is highly damaged.

Moreover, when a side-by-side type of composite filament having a latent crimpability, in which two or more polymers have been arranged highly eccentrically in the cross section of a unitary filament, has been heretofore produced, it has been necessary to use polymers having similar chemical configuration and property in order to prevent separation of each component of the polymers after spinning, so that in general, a copolyamide has been used in combination with a homopolyamide. In order to make the crystal structures of the both polymers in these fibers different as far as possible and to increase the difference of shrinking property, that is, to increase the latent crimpability, although it is preferable to increase acopolymerization ratio of the copolyamide, the stickiness phenomena are remarkably increased as the copolymerization ratio increases, so that the copolymerization ratio must be limited fairly, and therefore, it has been difficult to prepare a side-by-side type of polyamide composite fibers having a satisfactory crimp developability.

The inventors have made various investigations in order to solve the above described problems resulting in accomplish ment of the present invention.

The object of the present invention is to provide fiber consisting of copolyamide, which has no stickiness without deteriorating the other excellent properties.

A further object is to provide a method of producing a practical fiber from polyamide having such a high copolymerization ratio that a practical fiber can hot be obtained as such due to a high stickiness.

The other object is to provide polyamide composite filaments having no stickiness but an excellent latent crimpability, which consist of a copolyamide and homopolyamide.

The above mentioned objects can be attained in such a manner that in melt-spinning a copolyamide, the copolyamide is previously mixed and contained homogeneously with a small amount of at least one normal paraffin selected from the group consisting of methane series hydrocarbons represented by the formula C,,H wherein n is an integer equal to or greater than 14.

The copolyamides to be applied to the method of the present invention include polyamides obtained by copolycon densating two or more polyamide forming compounds selected from the group consisting of lactams, w-aminocarboxylic acids and salts of diamines and dicarboxylic acids, for example, the polyamide forming materials such as, 'y-butyrolactam, 6-valerolactam, e-caprolactam, heptolactam, 6- aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, ll-aminoundecanoic acid or salts of diamines, such as, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, metaxylylenediamine, paraxylylenediamine, bis ('y-amino-propyl) ether, N,N'-bis(waminopropyl)piperazine, 1,1l-diam'inoundecanone'6 and dicarboxylic acids, such as, terephthalic acid, isophthalic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecandicarboxylic acid, hex ahydroterephthalic acid, diphenylene-4,4 dicarboxylic acid, diphenylmethand-4,4'-dicarboxylic acid, diphenylether-4,4'- dicarboxylic acid, diphenylpropane-4,4'-dicarboxylic acid, or salts of diamines and dicarboxylic acid derivatives or salts of diamine derivatives and dicarboxylic acids.

Furthermore, these copolyamides involve copolyamides added with inorganic or organic substances of delustrants, pigments, dyestuffs, light stabilizers, heat resistants, antistatic agents and plasticizers.

The normal paraffins which may be used in the invention are alkanes represented by the general formula C,,H having a straight chain structure with r1314. Forexample, mention may be made of tetradecane, pentadlecan, hexadecan, heptadecane, octadecane, nonadecand, eicosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, triacontane, dotriacontane, pentratriacontane tetracontane, pentacontane, hexacontane, dohexacontane, tetrahexacontane, heptacontane and etc.

Those which, contain a small amount of isoparaffin and cycloparaffin in addition to said normal paraffins such as found in some of the articles on the market, may also be used. These can be used singly or in combination of two or more of them.

All of nor'malparaffins having less than 14 carbon atoms are not suitable to use in the present invention, since they have relatively low melting points and tend to volatilize during heat treatments such as polymerizing process and melt-spinning process, thus failing to attain the intended merits of the invention. Among the normal paraffins, there are natural ones contained in petroleum and synthetic ones, but it is advantageous in cost to use natural paraffins or those which are obtained by refining the same. As to natural paraffins, those which have carbon atoms up to 70, i.e., up to heptacontane, are well known, and these paraffins having molecular weight up to such extent can satisfactorily be employed in the invention. The extent of molecular weight has no appreciable effect on the merits of the invention.

The above mentioned normal paraffins having carbon atoms equal to or greater than 14 are applied in such a manner either that they are added to copolyamide materials, followed by polycondensation reaction or that they are added thereto during the polycondensation reaction or after the completion of polycondensation reaction andthen the resulting mixture are subjected to mixing and agitation so as to be homogeneously dispersed. The copolyamide containing normal paraffin in a homogeneously dispersed state will be melt-spun by usual practice either intact or after being formed into fine particles or fine chips. The good results can also be obtained by applying paraffin to or mixing it with the fine particles or fine chips of paraffin-free copolyamide and then subjecting the particles or chips to melt-spinning, whereby the paraffin is homogeneously contained in the spun yarn during the spinning. In either case, it is important that parafi'ins to be contained in copolya' mide in a molten state must be exist in a homogeneously dispersed state. From this point of view, the method in which paraffin is added to raw copolyamide materials and polymerization is the effected, has such an advantage that a homogeneously dispersed state can be attained without mechanical means. In such a case that the addition of paraffin is effected during or after polymerization, a mechanical or physical mixing and dispersing operation such as agitation or shaking may be effected, when required. Such operation may also be effected by a screw, pump or the like in a melt extruder.

The content of the normal paraffin for attaining the objects of the invention is suitably within a range of 0.0 1-5 percent by weight based on the copolyamide. In case of less than 0.01 percent by weight, the effect for preventing stickiness is insufficient, while in case of more than 5 percent by weight, yarn breakage is developed during the manufacture of fiber and the drawing step, and further the quality of the fiber is deteriorated, so that it is not preferable.

The paraffin added and dispersed according to the method mentioned above satisfactorily maintains the dispersed state for a long time in the molten copolyamide, so that under the usual melt-spinning conditions both of the two components do not separate each other to separate out the paraffin.

The mechanism of the sticking phenomena between the fibers of copolyamide have been hardly made clear, notwithstanding it may be presumed that the moisture contained in the oil composition contributes to the stickiness since a remarkable sticking phenomena are appeared when an aqueous emulsion is imparted to the spun filament.

It is therefore assumed that the n-paraffins contained in the copolyamide according to the method of the invention disturb the mutual action between the fiber and water resulting in having an ability to prevent the stickiness, although the detailed mechanism and function thereof are not yet clear.

According to the addition of n-paraffins, the stickiness of the copolyamide may be never developed and moreover the copolymerization ratio which has heretofore been considerably restricted owing to the increase of the stickiness is relatively increased, whereby the polyamide fiber free from stickiness while having an extremely high heat shrinking property can be obtained. Furthermore, within the above range of the content amount of n-paraffin, the strength, elongation, dyeability, hygroscopicity, elastic recovering property and the other desired properties are not substantially decreased.

Moreover, although composite filaments obtained by melting the copolyamide containing the n-paraffins according to the invention and well known homopolyamide separately and by spinning them from the common orifice simultaneously have a good mutually bonding property of the both polymers and also the copolymer does not shown any stickiness, the latent crimpability is increased due to the high heat shrinking property and the fiber having extremely excellent crimpability and bulkiness can be obtained by heat treatment.

The fiber consisting of or comprising the copolyamide melt spun according to the method of the invention can be treated uniformly and easily in a treatment with an oil composition, taking up, drawing after spinning and the succeeding knitting and weaving processes without accompanying any disadvantages, such as, bad unwinding from a bobbin or stickiness between fibers as in a conventional homopolyamide fiber and furthermore the treatment velocity can be further increased.

Furthermore, the fibers obtained by the method of the invention are provided with the excellent properties as described above which have never been seen in conventional homopolyamide fibers, so that they are preferable as raw material for producing various clothings, interior decorations, commercial articles, etc. by using solely or in combination with the other fibers. Particularly, if said fibers are mix-spun or mix-woven with the other fibers and then subjected to heat treatment by utilizing the high shrinking property interesting fancy yarns or fancy fabrics can be manufactured.

For a better understanding of the invention reference is made to the accompanying drawings:

FIG. 1 is a graph showing a resistance of a well known and undrawn copolyamide yarn in unwinding it from a bobbin; and

FIG. 2 is a graph showing a resistance of the undrawn copolyamide yarn improved by the method according to the invention in unwinding it from a bobbin.

The invention will be explained further in detail by the following examples, in which parts and means parts by weight and by weight unless any special reference provided.

EXAMPLE I To parts of e-caprolactam and 15 parts of hexamethylenediammonium isophahalate was added 3/300 mol of acetic acid as a viscosity regulator and further 0.5 percent of paraffin (produced by Wako .lunyaku K.K.) having a melting point of 64 C. and consisting mainly of triacontane and the resulting mixture was heated in the nitrogen gas atmosphere at 250 C. for 7 hours under a normal pressure to conduct copolymerization, whereafter the reacted product was extruded from bottom of a reactor in the form of strip to permit passing through water bath so as to be cooled and solidified, which was then cut into copolyamide fine granules of 3 mm. X 3 mm. The thusly obtained fine granules were washed with hot water of approximately 80 C. to remove monomer therefrom and dried by a vacuum drier at 80 C. under 0.1 mm.I-Ig. to reduce the water content to 0.07 percent and whereafter supplied to a heat grid type of melt-spinning device. After residence for 40 minutes, the copolymer melted at 270 C. was extruded from nozzles and applied with the spinning oil composition consisting of an aqueous emulsion by means of the rotary roller and then taken up on a bobbin as an undrawn yarn having 287 11/34 filaments.

Moreover, the polymerization and the spinning were carried out under the same condition as the above, except that paraffin was not added, to produce a undrawn yarn consisting of copolyamide of the same denier filaments which was adapted as a control yarn. In any case, there perceived no yam breakage and the other barriers on spinning.

The resulting two yarns were determined with respect to stickiness degree by the following means. That is, a bobbin was arranged at right angle to the bottom thereof. A tension meter (TI-80 type made by Toyo Sokki Co.) was located at a position right above the bobbin and separated from it cm. along the extension line of the bobbin axis.

A guide was secured to a point separated I2 cm. from the tension meter along a line inclined by 20 from the bobbin axis. A winding machine was arranged at a position located horizontally with respect to the guide.

In the thus arranged apparatus, the yarn unwound from the bobbin was passed through the tension meter and taken up by the winder through the guide. The unwinding resistance of the yarn perceived on the tension meter was recorded on a chart by means of a pen writing recorder (WTR-2l I type made by Watanabe Sokki Co.). In the determined conditions, the takeup velocity was m./min. and the graduation of 1 cm. in the chart to record the unwinding resistance of yarn was adjusted so as to correspond to a resistance of 5 g. load.

The results obtained by determining the resistances of the above-described two filaments from bobbin are shown in FIGS. 1 and 2, respectively.

FIG. I is a diagrammatical view of a control yarn containing no paraffin, which shows a stickiness corresponding to 8 to 11 On the other hand, FIG. 2 illustrates a resistance of the sample used in the method according to the invention which exhibits the resistance of only I to 2 g.

Moreover, these two yarns taken up on the bobbins were drawn to 4.1 times their original length and as the results the control yarn was developed with the yarn breakage simultaneously with starting the drawing machine, so that the drawing could not be performed. On the contrary, the yarn containing paraffin was normally drawn without developing any yarn breakage.

EXAMPLE 2 To 10 kg. of 3 mm. X 3 mm. fine particles of copolyamide such as produced in example 1 and containing no paraffin was added 0.l percent of paraffin (manufactured Wako Junyaku ILK.) having a melting point of 38 40 C. and consisting mainly of heneicosane in powder form. The resulting mixture was filled into a regular hexahedron type rotary mixer which, in turn, was then sealed and rotated at 4 revolutions per minute for 3 hours, in order to adhere the paraffin to uniformly to the fine particles. The resulting fine particles were then supplied to a screw type melt extruder (Model YE4NT, manufactured by Yamakawa Tekko Seisakusho K.K.) in order to work again and form 2 mm. X 2 mm. fine particles, which were then dried under a reduced pressure to reduce a water content to 0.065 percent, and whcreafter they were melt-spun by usual practice by means ofa heat grid type melt-spinning device. Then the extruded copolymer was ap plied with an aqueous emulsion oil composition and then taken up on a bobbin as a undrawn yarn having 400 (1/34 filaments. The yarn taken up on a bobbin was measured as to the unwinding resistance in accordance with the method described in example I, and a resistance value of only 2 to 3 g. was recorded. Further, the yarn could be subjected to drawing process to obtain a uniform drawn yarn with no trouble.

EXAMPLE 3 To l parts of salt of N,N-bis(w-amino-propyl)piperazine and adipic acid and 90 parts of salt of un dccamethylenediamine and tcrephthalic acid was added, as viscosity stabilizer, hexamethylcnediaminc in an amount of 1/300 mol based on the raw material for polycondensation and was further added 5 percent of paraffin (manufactured by Wako .lunyaku K.K.) having a melting point of 70 to 73 C. and consisting mainly of pentatriacontane. The resulting mixture was then heated at 32 C. for 6 hours in the nitrogen gas atmosphere to effect polycondensation, whereaftcr the resultant mass was extruded through the bottom of reaction vessel and then the extruded copolyamidc was cut off to form 3 mm. X 3 mm. fine particles. The fine particles were washed with water and dried under the same conditions as in example 1, followed by melt spinning to form a filament, which, after being treated with an oil composition, was taken up on a bobbin to provide a l60-denier monofilament bobbin-wound yarn.

Further, a l60-denier monofilament yarn was produced under the same conditions as described above except that without the addition of paraffin, which was a control yarn,

The unwinding resistance of these two bobbin-wound yarns were measured by the method adscribed in example 1. The control yarn showed extreme stickiness with a resistance of as high as 5 to 8 g. while the paraffin-containing yarn recorded a minimum resistance of only I to 2 g. Further, when these samples were subjected to drawing process, the paraffin-containing sample could be drawn smoothly without causing yarn breakage to form a uniform drawn yarn, whereas the sample free from paraffin encountered frequent yarn breakages and could not be formed into a homogeneous drawn yarn because of the irregularities in tension. These drawn yarns were measured with respect to the dyeability, hydroscopicity, elastic recovering property and etc., but there was found substantially no difference therebetween in thesepropertics. Thus, it was ascertained that the effect of paraffin on these properties was negligible.

EXAMPLE 4 To 20 parts of salt of metaxylylenediamine and adipic acid and 80 parts of e-caprolactam was added, as viscosity stabilizer, acetic acid in an amount of 1/300 mol based on said raw material for polycondcnsation and was further added 0.05 percent of liquid paraffin (manufactured by Wako Junyaku K.K.) consisting of tetradecane, pentadecane, hexadecane and heptadecane. The resulting mixture was then heated at 250 C. for 7 hours in the nitrogen gas atmosphere to mides were produced under the same condition as described above except that without the addition of paraffin.

Further, a preparation obtained by adding 0.5 percent of aminocaproic acid to e-caprolactam and further adding acetic acid in an amount of0.3 mol based on said raw material for v polymerization, was subjected to the processes ranging from polymerization to chip drying under the same conditions as mentioned above, to obtain 2 mm. X 2 mm. Nylon-6 fine particles which had water content of0.0()8 percent.

These Nylon-6 fine particles and the above-mentioned paraffin-containing copolyamide fine particles were supplied to a heat grid type melt spinning apparatus for producing composite filament, separately melted therein and simultaneously spun through a common orifice to form a 280 11/18 filaments side-by-side type undrawn filament (conjugating ratio lzl), which was applied with a spinning oil composition consisting of aqueous emulsion and then taken up on a bobbin. Let us designate it as filament (A)". On the other hand, the above mentioned Nylon-6 fine particles and paraffin-free polyamidc fine particles were subjected to conjugate spinning, oil composition treatment and taking up in the same manner, to produce a composite undrawn filament, which is designated as filament (8)".

The degree of stickiness of the filaments (A) and (B) were measured by the method described in example 1, and it was found that the filament (A) showed an unwinding resistance of only 0.2 to 0.3 g. whereas the filament (8) showed a resistance of 3 to 5 g. Further, the drawing operation of the filament (B) was found difficult as in the filament (B) frequent yarn breakages were occurred. The two drawn samples were measured with respect to the strength, elongation, crimpability, dyeability, hygroscopicity and etc., but there was no signifi cant difference therebetween in these properties, so that the effect caused by the addition of paraffin was not recognized.

What we claim is:

l. A composite filament having a latent crimpability and a reduced stickiness, which comprises a copolyamidc obtained by copolycondensating at least two polyamide forming mem bers selected from the group consisting of lactams, waminocarboxylic acids, and salts ofdiamincs with dicarboxylic acids; and a homopolyamide obtained by polycondensating a polyamide forming compound selected from the group con sisting of lactams, w-aminocarboxylic acids, and salts of diamines with dicarboxylic acids; said copolyamide having homogeneously dispersed therein, a small amount of at least one normal paraffin selected from the: group consisting of methane series hydrocarbons represented by the formula C,,H wherein n is an integer of at least 14.

2, A method for producing nonsticky copolyamide-containing fibers comprising: separately melting a copolyamide and a homopolyamide, said copolyamide being obtained by copolycondensing at least two polyamide forming members selected from the group consisting of llactams, w-aminocarboxylic acids, and salts of diamines with dicarboxylic acids, and said homopolyamide being obtained by polycondensating a polyamide forming compound selected from the group consisting of lactams, w-aminocarboxylic acids, and salts of diamines with dicarboxylic acids; homogeneously mixing with said copolyamide a small amount of at least one normal paraffin selected from the group consisting of methane series hydrocarbons represented by the formula C,,H,,,, wherein n is an integer of at least l4; and simultaneously spinning said copolyamide and said hompolyamide through a common spinning nozzle.

3. A method as claimed in claim 2, wherein said amount of the normal paraffin is within a range offrom 0,0l to 5 percent by weight based on the copolyamide. 

2. A method for producing nonsticky copolyamide-containing fibers comprising: separately melting a copolyamide and a homopolyamide, said copolyamide being obtained by copolycondensing at least two polyamide forming members selected from the group consisting of lactams, omega -aminocarboxylic acids, and salts of diamines with dicarboxylic acids, and said homopolyamide being obtained by polycondensating a polyamide forming compound selected from the group consisting of lactams, omega -aminocarboxylic acids, and salts of diamines with dicarboxylic acids; homogeneously mixing with said copolyamide a small amount of at least one normal paraffin selected from the group consisting of methane series hydrocarbons represented by the formula CnH2n 2, wherein n is an integer of at least 14; and simultaneously spinning said copolyamide and said hompolyamide through a common spinning nozzle.
 3. A method as claimed in claim 2, wherein said amount of the normal paraffin is within a range of from 0.01 to 5 percent by weight based on the copolyamide. 